The generally used grand /piano or upright piano gives a touch effect or a connection effect which is produced when the pressed key is engaged with something and is released immediately after descending 7-7.5 mm. However, all the electronic /musical instruments which have been used so far did not give such an after-touch effect, and therefore, players of electronic musical instruments could not feel such an after-touch effect, with the result that the players felt confusions and other difficulties. Therefore, there have been brisk activities among the concerned corporations and private researches in order to develop an electronic musical instrument which is capable of giving some effect which is similar to the after-touch effect. As a result of such efforts, a number of patent applications have been filed, but only a few of them have been put to practical uses. However, these which have been put to practical uses are far from giving the exact after-touch effect which is seen in the non-electronic usual pianos.